Chemistry of Unprotected Amino Acids in Aqueous Solution:Direct Bromination of Aromatic Amino Acids with Bromoisocyanuric Acid Sodium Salt under Strong Acidic Condition

摘要

Brominations of unprotected aromatic amino acids such as phenylalanine,tyrosine,and glycine,with bro- moisocyanuric acid mono sodium salt (BICA-Na) were conducted in 60% aq.H_2SO_4 at 0 deg C to give a mixture of mono-brominated products in good yield.Unexpectedly,meta-bromophenylglycine was obtained as main product accompanied by ortho-and para-substituted products,while phenylalanine gave only ortho-and para-substituted products.Bromination of 2-phenylethylamine or benzylamine showed a tendency similar to the corresponding amino acids.